Embedded PC: CE Images General Information



Target platforms

TcTimer functionality is available on BECKHOFF CE based devices (like CX1000 / CX1020 / CX9000 / Ethernet Panel/ IPC...)


PDF Overview



TcTimer provides a deterministic timer allowing to execute e.g. customer C++ code instead of implementing logic within IEC61131-3 PLC languages.

The basic TcTimer is scalable from 100µs and is derived from highest CE proirity level. The TwinCAT-R3IO-API offers direct access via pointers to in/out-put image of TwinCAT IO task.

The required TwinCAT IO task can be configured remotely with TwinCAT System Manager. This tool helps to easy scan the IOs on connected fieldbusses and map the physical field IOs to logical IOs in IO-Task.

Data-consistency : After reading the input data from IO task, calculating and providing new data in the output image the C++ code can trigger the data exchange between IO task to mapped physical IOs : As a result data-consistency from logical C++ code down to physical IO level is provided.



Major differences between TcTimer and TwinCAT IO R3

General the two solutions TcTimer and R3IO are similar : Both solutions offer an API to access from C++ code the images from TwinCAT-IO-tasks.

The major differences are this :

Required Components

The components to implement applications are here



// Set the Priorities of the Thread
if (CeSetThreadPriority(hThreadTask1, 26) && CeSetThreadPriority(hThreadTask2, 27))

The sample sets thread-prior to 26 and 27.

In general the user can set the thread-priority, see additional info about priorites from other threads  :

- Device threads : 100-130 approx.
- Beckhoff TwinCAT Timer thread : 1

- Microsoft MultiMedia Timer : 2


Depending on the requirements of your application it make sense to choose priority 3 - 64 for real time threads and priority 131 - 255 for non real time threads.